Circuit interrupter



June l, 1948. J. M. WALLACE Er A1. 2,442,477

CIRCUIT INTERRUPTER Original Filed June 24, 1941 2z Q a! 26 ATTORNEYPatented June 1, 1948 clacurr m'rERRUr'rEn James M. Wallace, Braddock,Herbert L. Rawlins, Pittsburgh, and James M. Cumming and Wayne S. Aspey,Turtle Creek, Pa., assignors to Westinghouse Electric Corporation, EastPittsburgh, Pa., a corporation of Pennsylvania Original application June24, 1941, Serial No.

399,452. Divided and this application November 10, 1944, Serial No.562,798

12 Claims. 1

This invention relates to electric circuit interrupters in general, andmore particularly to automatic reclosing circuit breakers.

This invention is a division of the subject matter of our copendingapplication on Circuit, interrupters, Serial No. 399,452, filed June 24,1941 and assigned to the same assignee of this inven'- tion.

`Automatic reclosing circuit breakers of the type with which thisinvention is primarily concerned, generally include separable contactswhich are biased closed, and are adapted to be separated in a closed arcchamber by electro-responsive means having lost motion therewith, topermit overtravel of the contacts dependent upon the pressure developedby the arc. may be provided for automatically retaining the breakercontacts separated in response to a predetermined number of closelysuccessive circuit interrupting operations, after which the contactsmust be manually reclosed.

One object of this invention is to provide, in a circuit breaker of thetype described which employs a liquid arc extinguishing medium and ameans utilizing said liquid for controlling the rate of Contactmovement, novel means controlling the supply of fresh liquid to thearcing zone to replenish liquid in the' arcing zone between successivecircuit interrupting operations.

Another object of this invention is to provide, in a. circuit breakerhaving separable contacts adapted to strike an arc in aclosed,liquid-filled, arc extinguishing chamber, novel means for replenishingthe liquid between successive circuit interrupting operations. i

Another object of this invention is to provide, in an automaticreclosing circuit breaker, novel means for delaying closing movement ofthe breaker contacts.

More specifically, it is an object of this invention to provide, in anautomatic reclosing circuit breaker, novel means for maintainingthe-contacts separated following a circuit interrupting operation, incombination with" time delay means for finally releasing said contactsto close the circuit.

These and other objects of this invention will become more apparent uponconsideration of the following detailed description of a preferredembodiment thereof, when taken in connection with the attached drawing,in which:

Figure 1 is a substantially central vertical section through a circuitbreaker embodying this invention with certain parts thereof shown inelevation;

In addition, meansl Fig. 2 is a partial elevational view of theoperating mechanism shown in Fig. 1;

Fig. 3 is a transverse sectional view of the breaker shown in Fig, ltaken substantially on the line III-III thereof with certain partsomitted.

Fig. 4 is a fragmentary sectional view of the A lockout integratingmechanism employed in the breaker shown in Fig. 1;

Fig. 5 is a view like Fig. 4 but showing the parts of the mechanism in adifferent position from that shown in Fig. 4; and

Fig. 6 is also a partial sectional view illustrating the mechanism ofFigs. 4 and 5 in a still different position of the parts thereof.

The circuit breaker constituting this invention is shown by way ofexample as being mounted in a tubular insulating casing 2 which may beof any desired insulating material, preferably porcelain or the like.The casing 2 is provided with a closed bottom and an open top, with thetop being closed by a cover assembly 4, and the bottom of the casinghaving associated therewith a terminal assembly B. Intermediate the endsof the casing 2 there is provided a cylindrical `surface 8, and asupporting bracket I2 is adapted to be clamped around this cylindricalsurface with resilient material I0 interposed between the clamp I2 andthe outer casing wall to prevent damage thereto.

The terminal assembly 6 at the bottom of the casing includes a terminalbolt I4 of conducting material adapted to extend through a substantiallycentral aperture in the bottom casing wall, and the bolt is providedwith an enlarged head I8 interiorly of the casing, with packing material20 interposed between the head I8 and the bottom wall of the casing. Anut 22 and washel 24 cooperate with bolt I4 to retain the same inposition, and a conductor 28 may be secured to the bolt, for example, asby a second nut 26. Bolt I4 is preferably provided with a substantiallycentral bore 30 for the purpose of draining casing 2, the lower endthereof being adapted to be closed by a screw-threaded closure plug 32.A

The upper end of casing 2 is ribbed, and a supporting flanged ring 34 isadapted to be secured to this ribbed portion of the casing, for example,as by cast metal, or the like, 36. Supporting ring 34 is adapted to havecover assembly 4 secured thereto in any desired manner, not shown.

The casing and terminal structure B described above are substantiallyidentica1 with those more particularly described and claimed in thecopending application of J. M. Wallace and H. L.

'sulating i spacer sleeves 64.

. A 3 Rawlins, Serial No. 374,688, tiled January 16, 1941, and in theirPatent No. 2,318,421, issued May 4, 1943, both oi which are assigned tothe same assignee as this application.

Cover assembly 4 comprises an integral casting having a ange'lj .formedintegrally with the lower end thereof and adapted to seat on the upperend wallof casing 2 and extend over the interior of the casing. FlangeIl is also provided with integral outwardly extending ears (not shown)adapted to be bolted to ears formed on supporting ring 64. The coverassembly casting is provided with a hollow portion including the topwall 40, side walls 42, Il and end walls 44 and 45, with 'the bottomoithe hollow portion being open and located over the open top of casing 2.At one upper corner oi the hollow portion oi cover assembly 4, aninclined wall -is provided with a threaded aperture for cooperationwith, a threaded ller plug 46, by means ot which casing 2 may be filledwith an arc extinguishing fluid. Top wall 40 of the hollow portion oithe cover assembly is extended beyond the hollow portion and slightlyinclined downwardly as at 48 to form the top wall of a sleet hoodportion having side walls 52 and 63. The top wall 4I of the hood portionterminates in an angularly downwardly extending lip 50, for a purpose tobe hereinafter described. e

As appears from Figs. 1 and 3 of the drawing, flange 38 of the coverassembly l has portions which extend over the open top of casing 2, andthese portions are adapted to insulatingly support the circuit breakercontacts and operating mechanism, for example, as by the tubular in- Thespacer sleeves 54 have the opposite ends thereof threaded forcooperation with screws 56 and 56, to secure the spacers to ange 38 andthe. upper leg |06 of a U-shaped supporting frame 60, respectively.'.l'he other leg |08 of U-shaped frame l0 is secured to one end of agenerally rectangular frame 6I. and the other end of this frame ispreferably kformed integral with the top cap 66 of an interrupterchamber 68.

The interrupter chamber 68 includes an insulating tube of liber or thelike, having one end threaded into top cap 66, and having the other endthreadedly received in a bottom terminal cap .14. Top cap 66 is providedwith a substantially central aperture 69 for closely slidably receivinga contact piston rod 12, and the cap is also provided with' spacedoutlet apertures 13 adapted to be controlled by a sliding valve plate|02, normally biased by a coil compression spring |04 into engagementwith the adjacent end oi.' insulating tube 10. 'I he lower end cap 14 ofthe interrupter chamber is provided with inlet passages 16, and with asubstantially centrally located threaded aperture for receiving thethreaded end of an adjustable ilxed contact 18 which is secured inposition, for example, as by a loci: nut 80. The outer end of end cap 14yis reduced in size to form a shoulder 62 4on which is seated one end ofa coil compression spring 84, with the other end of this spring bearingagainst the head I8 of terminal bolt Il. Spring Il should be of somegood resilient conducting material. such, for example. as a copper alloyor the like.

The lower end of contact piston rod 12 is provided with a socket forreceiving the upper end or contact rod 86, secured in the socket, for example, as by a rivet 08. The lower end ot contact rod 86 is enlarged toform a contact head a central aperture 6| so that the piston may beslidably mounted on contact rod Il for movement between contact head l0and the lower end of contact piston rod 12. The lower end of contactpiston rod 12 is counterbored to receive a coll compression spring 03which normally operates to bias liquid directing piston 92 towardscontact head 90, As shown, piston 62 is provided centrally with a hollowportion to which access is obtained by means oi' a plurality oi topapertures 04, and a single lower aperture 05 concentric with contacthead 00 so as to form an annular liquid passage therewith. Liquiddirector piston I2 may have a. peripheral slot for the reception of apiston ring 96 to kprevent leakage of liquid between the piston andinner wall of tube 10. A stop ring 08 is secured in position between thelower end oi insulating tube 10 and lower end cap 14 and, as shown,projects inwardly so as to form a stop for liquid director piston 02, sothat when the contacts are closed, the piston is maintained in aposition intermediate the limits of its movement on contact rod 86. Theinlet apertures 'I6 in cap 14 are adapted to be controlled by a checkvalve plate |00 freely mounted between the end wall of end cap 14 andstop ring 98. The interrupter chamber described above is substantiallyidentical with that described and claimed in the above-mentionedcopending application of J. M. Wallace and H. L. Rawlins, Serial No.374,686, except that in the interrupter chamber herein described, valveplate |02 is spring biased in one direction, rather than beingfrictionally associated with' contact piston rod 12 as in the saidcopending application.

The operation of the interrupter chamber herein disclosed andillustrated is subtantially the same as that in the above-identifiedcopending application and comprises, briefly, utilization of iluidpressures generated by an arc drawn, to obtain contact separation. Thisis accomplished by the instant structure, because it will be observedthat as soon as contact piston rod 12 isv moved upwardly and contacthead 90 moves out of engagement with ixed contact 10 to strike an arc,the action of such an arc on the arc extinguishing liquid within thechamber, such, for example, as oil or the like, will decompose the sameto generate a gas which will build up a pressure within chamber 68. Assoon as this pressure builds up, it will obviously force check valveplate |00 and valve plate |02 outwardly relative to insulating tube 10to close both the inlet and outlet apertures 16 and 13, respectively.Outward movement of valve plate |02 readily I occurs because the upperside of this plate is vented by aperture |03. Accordingly, suchpressures within the chamber will act on contact piston rod 12 in apiston-like manner to force the same to move outwardly of the chamber,and thereby increase the contact separation. In the upward movement ofcontact rod '86, liquid director piston 92 remains stationary untilcontact head engages the upper wall of the director to thereby draw thearc out to an optimum length before moving the director to cause a iiowot liquid through apertures 94 and 96 and into the arc to extinguish thesame. Contact piston rod 12 and contact rod 86 will be moved outwardlyby the pressure developed within arc chamber 68 until the combinedaction of attenuation of the arc and dow of liquid therethrough causeextinction. As soon as the arc is extinguished. the contact piston rod12 is adapted to be moved downwardly towards iixed contact 16 in amanner to be hereinafter further described. and since pressure is nolonger being generated within the chamber, spring |04 will be free tomove valve plate |02 downwardly to open outlet passages 18 and permitexhaust of gasesv and used liquid out of the upper end of the arcchamber. This up-flow of gas and used liquid from the chamber will betaken care of by an ini'iow of fresh liquid through inlet apertures 18,which will cause check valve plate to be unseated due to the pressure atthe bottom of the casing because of the head'of liquid therein, andyespecially because of the difference in pressure due to the diilerencein the head of liquid between inlet apertures 18 and outlet apertures18. Consequently, it can be seen that the fluid pressure developed bythe arc is utilized in this interrupter to-obtain contact separation,and that during a closing operation of the breaker contacts, the usedarc extinguishing uid within the chamber is replaced by fresh fluid fromcasing 2.

As previously stated, the substantially U- shaped supporting framemember 80 is secured to the upper end of rectangular supporting frame84, and the frame member 60 is for thepurpose of supporting a solenoidcoil ||2. The upper and lower legs |06 and |08 of supporting member 80are connected by spaced integral legs ||0vposi tioned at one sidethereof, so that the solenoid coil ||2 may be assembled with support 60by merely slipping the entire coil between legs |08 and |08 through theopen side of support 60. The legs |05 and |08 of the U-shaped frame 60are provided with aligned apertures adapted to coincide with the centralbore' provided in solenoid coil H2, and a securing sleeve I4, ofinsulating material, is adapted to be inserted through the aperture inleg |08 of the U-.shaped support 80 into engagement with a shoulderedplug IIS seated against a shoulder provided about the aperture throughleg |06 of U-shaped supporting frame 80. Securing sleeve ||4 ismaintained against movement downwardly from the supporting frame 80, asviewed in Fig. 1, by the connection of rectangular frame 64 thereto,inasmuch as the end plate ||8 of this frame is provided with ashouldered aperture, with the adiacent end of securing sleeve ||4 seatedon the shoulder of this aperture to prevent movement thereof withrespect to U-shaped frame 60. Frame 80 is of magnetic material to form astationary frame for coil ||2 as well as a support therefor. Rectangularframe 84 is secured to the lower leg |08 of U-shaped frame 60. forexample, as by screws 62, or the like. It will be noted that solenoidcoil ||2 is provided with a. plurality of taps ||8 which are connectedto different sections of the coil, and located away from the connectinglegs ||0 of the U-shaped support 60, at the open side thereof so as tobe readily accessible for the purpose of changing the coil connectionswhen desired. Rectangular supporting frame 84 is provided with the sideplates integral with top plate |,|8 at one end thereof, and with top cap88 for the interrupter chamber at the other end thereof.

The upper end of contact piston rod 12 is peripherally grooved as at |22to f-orm a notch and a latch projection |24 at the upper end thereof,for cooperation with a latch lever |28. The latch lever is adapted to'be pivotally mounted on top end cap 88 of the interrupter chamber,

|28, respectively, for biasing the latch lever in a clockwise directionabout its pivot, as viewed in Fig. 1. 'I'he latch lever is provided witha plurality oi' latch lugs |82 and |84 for cooperation with the latchprojection |24 on the upper end of contact piston rod 12, and with thecore of solenoid coil |i2. A contact operating rod |88 is rigidlysecured to contact piston rod 12 and extends from the upper end thereofthrough a sleeve |81 extending through the central opening 0f solenoidcoil ||2 and securing sleeve ||4. The lower end of sleeve |81 isenlarged as shown at |88 to receive the upper end o'f a coil compressionspring |44. with the lower end thereof bearing against the bottom wallof a tubular solenoid core member |48. The tubular solenoid core |40,which is of magnetic material, has the bottom wall thereof apertured tobe slidably mounted on contact operating rod |88. and has adjacent theupper end thereof a peripheral inwardly extending rib 42 of a size toclosely engage the outer surface of enlarged portion |88 of sleeve |81.Adjacent the lower end of solenoid core |40 are radially directed ventapertures |48, for a purpose to be hereinafter described.

In the operation of the mechanism thus far described, it will beapparent that upon the occurrence of predetermined circuit conditions,solenoid coil |2 will become sufficiently energized to attract core |40and cause it to move upwardly on operating rod |88 and compress spring|44 between the core and sleeve |81. Furthermore, because of the closefit between core |40, securing sleeve 4 and enlarged portion i'38 ofsleeve |81, and since these parts are all immersed in the arcextinguishing fluid, it will be obvious that upward movement of core |40will be relatively slow because of the necessity of displacing the fluidwithin securing sleeve- |4 through the relatively small clearancebetween the core and sleeve. However, after suillcient movement of thecore upwardly so that rib |42 clears the upper end of enlarged sleeveportion |88, there will then be a relatively large annular passagethrough core 40 and outlet apertures |48 for liquid entrapped insecuring sleeve ||4, so that further movement of core |40 upwardly willtake place at a relatively rapid rate. During this rapid movement of thecore, the bottom wall thereof will engage the lower end of enlargedsleeve portion |38 to cau-se movement of the sleeve upwardly with thecore, and engagement of the upper end of the sleeve with shoulder |41formed on contact operating rod |88, will thus quickly separate contacthead from fixed contact 18. This movement of contact head 80 by solenoidcore |40 away from fixed contact 18 need be but a small amount, becauseas soon as the contacts are separated suiflciently to draw an arc, thepressure generated by such an arc operates to increase the contactseparation ysufficiently to extinguish the arc. Obviously because of thesliding connection of solenoid core |40 with respect tocontact operating rod |88, the contact operating rod and contact head 80 arepermitted to have a considerable overtravel independent of solenoid core40 'in response to pressures built up within the interrupter chamber 68.As soon as the arc is extnguished and the pressure drops withininterrupter chamber 88, contact operating rod |36 is permitted to movedownwardly to reclose the contacts. However, its downward motion ishalted by engagement of latch projection |24 at the top of contactpiston'rod 12 with upper latch lug |82. In the meantime, solenoid core|40 returns very slowly under the biasing forces of gravity and spring|44, to the position shown in A }'Fig.,1. because of the dashpot actionthereof in securing Ysleeve ||4, so that considerable time"'jmuste'lapse until the solenoid core |40 moves down into engagementwith the upper end of vlatch lever |25. vand therebycausescounterclockwise rotation of the latch lever to disengage its upper lug|32 from contact piston rod projection core |40..

The reason why a plurality'of lugs |32, |34 are provided on the latchlever to successively halt downward movement of contact head 90 towardsilxed contact 15 is that it is necessary tomaintain the contactsseparated, during the 4time delay period before reclosure,'a lsuicientdistance apart so that the dielectric therebetween will be `capable ofsafely withstanding circuit voltage. Because of contamination and.deterioration ofthe dielectric on the interruption of high currentarcs, this4 distance is quite large. n the other hand, it is desired tomake thev time delay between a circuit interrupting operation and areclosure of the circuit as long as possible with the available timedelay means including the dashpot comprising solenoid core |40 andsecuring sleeve ||4. Lug |32 on the latchlever, therefore, is positionedto engage the moving contact to hold it separated from fixed contact 18a distance corresponding to the safe gap therebetween according to thedielectric being used. If lug |34 were not also provided on the latchlever, then the time delay between a circuit interrupting operation anda reclosure of the breaker contacts would'be too short, and accordingly.to lengthen this period, the second llug |34 is provided for momentarilydelaying reclosure of the breaker contacts after release of the movingcontact from lug |32, to thereby obtain a longer time delay in reclosingwithout undue danger of ilashover, inasmuch as the period of time whichlug |34 operates to maintain the breaker contacts separated is so shortthat ionization of the path between the breaker contacts does not havetime to be completed prior to reclosure of the contacts. Also oninterruption of low currents, the pressure maybe insumcient to movecontact projection |24 as high as latch lug |32 and since the dielectricwill not be unduly impaired by low current interruptions, engagementwith latch lug |34 will provide a safe gap between the contacts whileusing full time delay on reclosure.

The upper end of contact operating rod |38 is pivotally secured as bypivot pin |50 to one end of a pair of insulating links |45, with theother ends of the links being connected to an angled crank lever |52,for example, as by the pivot pin |53. Crank lever |52 is pivotallymounted at its other end on a shaft |54 extending across the hollowportion of the top cover casting, and its outer ends are mounted in'apertures provided in the side walls 42 and 43 of the cover relativeendwise movement of shaft |54.

hollow portion, with the outer ends of these apertures being closed byscrew plugs |55 to prevent Angled crank lever |52 is rotatably mountedon shaft |54, 'and a generally U-shaped yoke |58 has the leg portionsthereof also rotatably mounted on shaft |54, with one leg of yoke |58pivotally connected to one end of toggle link |50, and the other ends ofthis toggle link being plvotally connected to a toggle lever |86, whichis, in turn, secured on the squared end of ashaft |55 rotatably mountedin an angled portion of end wall 46 of the cover assembly in a bearingsleeve |12, by a. bolt |10, which also acts to secure an operatinghandle |14 to the other squared end of shaft |65. Operating handle |14is provided at the outer end thereof with a hook eye aperture |18 forthe reception of a hook stick or other operating member.` Actuatinghandle |14 is limited in its movement in a counterciockwise direction bya stop screw |15 winch. may be secured in an adjusted position, forexample, as by a lock nut |80.

rA pair of concentric coil springs |52 and |54 are provided about shaft|54 within the hollow portion of the cover assembly 4, with one end ofthe outer large diameter coil spring |84 engaging flange 35 of the coverassembly, and the other end |58 thereof engaging the connecting portionl |89 of yoke |55, to thereby bias the yoke for movement about shaft |54in a counterclockwise direction. This movement of the yoke is normallyprevented by virtue of the toggle formed by links |60 and |66 beingbelow their dead-center position when actuating handle |14 is inengagement with stop screw |15. One end of the smaller diameter innercoil spring- |82 is extended to engage the angled portion of crank lever|52. and the other end of this spring also engages the connectingportion |59 of yoke |55, so that when the yoke is locked by togglelevers |60 and |66 against movement in a counterclockwise direction,biasing spring |82 will operate to bias crank lever |52 downwardly or ina clockwise direction relative to shaft |64, to thereby bias contactactuating rod |36 and contact head 90 downwardly, and cause engagementof the contact head with fixed contact 18.

The circuit through the interrupter herein disclosed extends from aterminal bracket |04 secured to the top cover assembly, for example. asby a. screw v|98 with the bracket having a terminai socket |96 for thereception of a line conductor, through the cover casting, by way of aconductor 200 to one tap I9 of solenoid coil H2, through the coil,conductor 202 to contact piston rod 12, contact rod 86, contact head 90,fixed contact 18, end cap 14, compression spring 04, terminal bolt |4.to another line conductor 20. Thus, it can be seen that the solenoidcoil ||2 is connected in series in the circuit including ythe breakercontacts, and as shown, the whole coil is connected in series, inasmuchas the end taps of the coil are used,- and, therefore, the connection isfor Ithe lowest rating of the Ibreaker which can be obtained with thecoil employed. inasmuch as the maximum iiux generating capacity of thecoil is employed to thereby obtain sumcient force to separate thecontacts on relatively low currents. To obtain higher current ratings,it would be merely necessary to connect conductor 202 or 200 to othertaps III of the coil to utilize smaller portions of the coil winding. Itwill be noted that the entire circuit breaker mechanism including thebreaker oontacts and interrupting chamber are supported as a unit withthe casing cover assembly 4, so that they may be removed with the coverfrom the casing when desired by merely unfastening the securing means ofthe cover to support 04 on the casing. Another feature of the particularsupporting means for the circuit breaker mechanism illustrated is thespecific support of the solenoid coil permitting ready replacementthereof by another similar coil, or by a coil having a different numberof turns to thereby change the available ratings of the breaker. Inorder to remove coll |I2, it is merely necessary to remove screws 02holding U-shaped frame 60 and rectangular frame 64 together. Thispermits securing sleeve i I to drop downwardly out of U-shaped frame 00,and then by removing one pivot pin, for example, the pivot pin |50, the

entire contact operating rod and sleeve |01 can be slipped out ofU-shaped frame 00 through apertures in legs |06 and |00 of the infame,whereupon coil I2 may be slipped laterally out of the open side ofU-shaped frame 00. To insert a new coil, it is simply necessary to slideit in the open side of U-shaped frame 60 until the bore therethrough isaligned with the apertures in legs |00 and |00 of the frame, whereuponcontact actuating rod |00 and securing sleeve ||4 may be insertedthrough the apertures and through the bore in the coil. and rectangularframe 04 secured to the lower leg |00 of the U- shaped supporting frameto thereby firmly secure the solenoid coil in operative position.Consequently, in order to remove the coil, it is only necessary toremove two screws 62 and one pivot pin |50.

The operation oi' contact`biasing spring |02 mounted on shaft |54 incover assembly 4 is believed to be obvious from the foregoing. In otherwords, when the circuit is interrupted by energization of solenoid coil||2 sumciently to raise core |40 and separate the contacts against thebias of spring |02, this spring will be eiective as soon as the circuitis interrupted to move the contact operating rod and contact head 00downwardly towards xed contact 10, until projection |24 on contactpiston rod 'I2 is engaged by latch lug |32, whereupon reclosure of thecontacts will be delayed until the latch is released by solenoid core|40 in the manner previously described.

In the event an overload occurs on the circuit which is notself-clearing but continues after a predetermined number of successiveinterrupting operations, there is provided means for tripping the togglewhich normally prevents rotation of yoke |50, so that spring |04 becomeseffective to rotate the yoke in a counterclockwise direction to thedotted line position shown in Fig. 1, and, consequently, raise cranklever |52, by engagement of the cross bar |00 of the yoke with aprojection |9| on the lever, together with contact actuating rod |06 andcontact head 90 to a position wherein the contact head is mainin thebottom wall thereof controlled by a ballcheck valve 2 I0 to permit ilowof liquid into tube 204, butpreventing outilow of liquid. A pistonmember 206 is slidably mounted within cylindrical tube 204, and theupper end thereof fis reduced in width, as shown at 226, to more closelynt guide rod 220. Contact actuating rod |36 is adapted to extend throughthe slot 224 so that the bottom portion of the pawl seats on flange 202formed on the upper end of sleeve |31 slidable on the contact actuatingrod. Guide rod 220 is formed with an intermediate shoulder on which awasher 220 is adapted to be seated, with a coi-l compression spring 200engaging between washer 220 and the lower leg of U-shaped pawl 222 tonormally maintain the pawl in the position shown in Fig. 4.

In the operation of the circuit breaker, it will be observed that eachtime solenoid core |40 is drawn upwardly to open the circuit and engagethe lower end of enlarged portion |30 of sleeve |01 to move the sameupwardly, that it will cause a tilting of pawl 222 against the bias ofspring 200, into engagement with notch 2|4 of piston 200 so thatcontinued upward movement will move the entire piston upwardly andthereby unseat ball-check valve 2|0 and cause a predetermined amount ofliquid to be drawn in the lower end of sleeve 204. As soon as thecircuit is interrupted, and the contact actuating rod and associatedparts are moved downwardly by biasing spring |02 in the mannerpreviously described, compression spring 200 on guide rod 220 isoperative to withdraw the upper leg of pawl 222 from the notch 2|4 inpiston 206, so that the piston remains at the position to which it hasbeen moved, while the contacts are reclosed. Now if the fault on thecircuit has been removed, piston 206 will gradually sink to the positionshown in Fig. 4 by displacement of the liquid below the piston throughthe relatively small clearance between the piston and cylindrical sleeve'204, so that eventually it will attain its original position shown inFigs. 1 and .4. However, in the event the fault in the circuit has notcleared upon the first reclosure of the breaker contacts, they willagain be opened by solenoid I2, and this tune pawl 222 will engage notch2|6 in piston 206, as shown in Fig. 5, inasmuch as the piston will nothave had time to sink to its original position and the piston will bemoved upwardly to the position shown in Fig. 6 of the drawing. As soonas the arc is extinguished, the contacts will again be reclosed bybiasing spring |82, and if the fault has cleared, piston 206 will againslowly sink to its original position as before. However, ii' the faulthas not cleared before piston 206 has an opportunity to sink much belowthe position shown in Fig. 6, the contacts will again be opened,

and this time pawl 222 will be pivoted into engagement with the lowernotch 2|8 in piston 206 and cause the same to be moved upwardly afurther amount and into engagement with the knee of the toggle formed bylevers |60 and |66 to move the knee of the toggle overcenter, therebyreleasing spring |64 and permitting the same to rotate yoke and move thetoggle levers and contact operating rod to the dotted-line positionshown in Fig. 1 of the drawing, wherein the breaker contacts aremaintained by spring |84 in y an open circuit position.

breaker contacts are now maintained in an open` circuit position. Whenpiston 206 has tripped the toggle, it will be observed that sincecontact operating rod |36 is maintained inan upper position, pawl 222will be maintained in engagement with notch 2|8 on piston 206 tomaintain the piston in its uppermost position. Accordingly, when it isdesired to manually reclose the breaker contacts .by movement ofoperating lever |14 in a counterclockwise direction to reset the togglelevers to the position shown in full lines in Fig. l, it will beobserved in the first place, that in the event it is thus attempted toclose the circuit while an overload is present, that the breaker istrip-free in that it is free to open against the i bias of contactbiasing spring |82 irrespective of the position of actuating lever |14.In the second place, it will bev noted that since piston 206 has had buta little time to move downwardly from its outermost position withrespect to cylindrical sleeve 204, that in the event the breaker isreclosed manually upon an overload in the circuit, that on theconsequent circuit interruption and movement of the contact operatingrod and associated parts upwardly, pawl 222 will be caused to engage thelower notch 2 |8,o1' piston 206 to therepfmove the toggle overcenter andagain permit spring |34 to maintain the contacts in an open position.

Thus, it can be seen that the circuit breaker herein disclosed iscapable of automatically opening the circuit with an inverse timecurrent characteristic due to the dashpot action of core |40 in securingsleeve ||4, and yet the contacts are separated with a relatively fastaction due to the venting of the dashpot formed by core |40 and sleeve|44 adjacent the end of its stroke. This feature is the invention of J.M. Wallace and is more particularly disclosed and claimed in hiscopending application Serial No. 399,453, filed June 24, 1941, nowPatent'No. 2,333,604, issued November 2, 1943, to the same assignee ofthis invention. Following a circuit interrupting operation, the breakercontacts are automatically reclosed with a time also due to the dashpotaction of core |40 and sleeve I I4, while maintaining substantially toadjacent the end of the timed period a safe gap between the breakercontacts. Also,

in `response to a predetermined number of closely successive circuitinterrupting' operations, novel means'arer provid'edi'formaintaining'the .breaker contacts 'in an 'openl position,- whichincludes la biasing' 'means 1normallyheld inactive by "a toggle which'isinoved over'centrlby a piston actuated a predeterminedqamount uponeach. interrupting operation ="Ihe' arc chamber: herein -disclosed isprovided with arl outlet valve. which is positive in i operation, andthe electroresponsive solenoid contact'opening means is supported-in amanner to'liender the same readily replaceable, and 'is provided with aplurality oftaps s'o that the -rating of the breaker may be `readilychanged. The specific arrangement oi' the contact closing spring and thespring for maintaining the contacts separated is especially importantwith respect to space considerations and eiiiciency of operation.

An operation counter 234 is adapted to be mounted on the end wall 45 ofthe hollow portion of cover assembly 4 and to be located beneath thehood portion thereof so as to be readily visible from the exterior ofthe breaker while protected from the elements by the hood. Thisoperation counter may be of any well known type provided with anactuating crank lever 236, mounted on an operating shaft extendingthrough the angled portion of wall 45 like shaft Hi8,v and with crank236 pivotally connected to an operating link 238I which, in turn, isconnected to pawl 222, so as to actuate the counter on each circuitinterrupting operation of the breaker. The connecting link 238 isprovided with an insulating portion,240 to insulate the counter frompawl 222.

There is preferably provided within the hollow portion of cover assembly4, in a socket 242 provided therefor on top Wall 40, a lightningarrester assembly, which may `be of any well known type includingelectrodes 256 spaced by an insulating plate 250 to form a gap in serieswith a porous block 260. in the circuit between top wall 40 of the coverand terminal 244 of the assembly. A tubular insulating sleeve 262 ispositioned between the assembly and the side wall of socket 242, andinsulating disk 210 supports terminal 244 and is secured to the coverassembly 4 by screws 266, with a sealing gasket 264 therebetween tomaintain the arrester assembly in socket 242. A shunt 263 connectsterminal 244 and a contact plate 21| and this plate is maintained incontact with block 260 by a spring 212. Thearrester terminal 244 isconnected by conductor 246 to the top leg |06 of U-shaped frame 60 tothereby form a circuit by-passing solenoid coil ||2. This obviouslywill-prevent the solenoid coil from opening the breaker contacts inresponse to surges inasmuch as the coil will co-operate with the shuntcircuit through the arrester assembly to by-pass such surge currentsaround the coil and limit the voltage across the coil insulation, and'such surges will be ineii'ective to cause a circuit interruptingoperation of the breaker. The arrester assembly herein disclosedutilizes a single series porous block and gap of the type shown in theplural series block and gap arrester shown in the patent to L. R.Ludwig. et al., No. 2,135,085, issued November 1, 1938. It will beunderstood that plural series porous block and gap assemblies may beused with this circuit breaker, if desired.

Also positioned beneath the hood portion of the cover assembly is atubular sight gauge glass 250, held in position against an integral lug248 on end wall 45 of the cover assembly, by an apertured threaded plug249, and an indicating rod 252 is slidably mounted through theapertur'ed plug and tubular sight glass, and is provided with a float254 secured tothe lower end thereof within casing 2 so that the level ofliquid within casing 2 may be readily determined from theexteriorthereof by inspection of the sight glass beneath the hood portion of thecover assembly. i

Thus, there is provided in a single unit anautomatic reclosing circuitbreaker characterized the coil insulation and prevent operation of thebreaker in response to the occurrence of surges in the circuit.Moreover, the cover assembly for the breaker casing 2 is arranged with asleet hood portion at one`side thereof to conceal an operating handlewhich is projected into view upon lock-lopen operation of the breakercontacts to direction. whereby to control closing movement 'of saidcontacts.

4. In a circuitinterrupter, a closed arc chamber. separable contacts insaid chamber at least indicate this condition, and also houses liquidmodifications may be made in this particular embodixnent withoutdeparting from the broad spirit and scope of the invention. Therefore,it is desired that the invention be interpreted as broadly as possibleand that it be limited only by the prior art and by what is expresslyset forth in the following claims.

We claim as our invention:

1. In a circuit breaker, separable contacts. electroresponsive means forseparating said contacts, means biasing said contacts closed, meansresponsive to circuit interrupting operation of said breaker forreleasably latching said contacts separated an amount at leastsuiiicient to provide a safe gap between the contacts which will notbreak down under impressed circuit voltage, time delay means adapted tobe set in operation in response to a circuit interrupting operation forreleasing said latch means a predetermined time thereafter, anotherlatch means adapted to automatically maintain said contacts separated alesser distance than said first latching means to prevent too quickreclosure thereof upon release of said iirst latching means, and saidtime delay means also being effective to release said lastmentionedlatch means a predetermined time after release of said iirst latchingmeans to permit said biasing means to finally close said contacts.-

2. In a circuit breaker, separable contacts.

- electroresponsive means for separating said contacts, means biasingsaid contacts closed. latch means for preventing quick reclosure of saidcontacts by said biasing means. said latch means including a` pluralityof spaced latch portions adapted to maintain said contacts diiierentdistances apart, respectively, and time delay means effective inresponse to a circuit interrupting operation to release said latchportions successively at predetermined times after a circuitinterrupting operation, respectively, and at least the iirst of saidlatch portions released by said time delay means adapted to ,maintain asafe gap .between said contacts.

Y 3. In a circuit breaker, separable contacts, electroresponsive meansfor separating said contacts. means biasing said contacts closed, latchmeans for preventing quick reclosure of said contacts by said biasingmeans, said latch means including a latch lever having a plurality ofspaced latch portions adapted to maintain said contacts diiierentdistances apart, respectively, said latch portions adapted to besuccessively effective to maintain said contacts separated saiddifferent distances and to be successively released upon movement ofsaid lever in one direction. time delay means effective in response to acircuit interrupting operation to slowly move said latch lever in saidone one of which is slidably mounted through a wall of said chamber in apiston-like manner, electroresponsive means having a lost motionconnection with said one contact to move said one contact outwardly ofsaid chamber and away from the other of said contacts and to permitovertravel of said one contact under the iniiuence of pressure generatedin said chamber by the arc struck when said contacts separate. meansbiasing said one contact for movement in a direction tol en- Sage 4theother of said contacts, latch means for automatically latching saidelectroresponsive means upon opening movementv thereof to preventreclosing movement of said one contact, said latch means effective tolatch said electroresponsive means at a plurality of positions at whichsaid one contact is held at different ldistleinces spaced away from saidother contact. respective# ly, at least the position of said one contactat which it is maintained the greatest ditsance from the other of saidcontacts providing a safe gap between said contacts, and time delaymeans operative in response to a circuit interrupting operation toactuate said latch means at predetermined times thereatter in a mannerto successively release said one contactto permit the same to move tosaid dinerent positions and i'inally into engagement with said othercontact, successively.

5. In a circuit breaker, separable contacts, electroresponsive means forseparating said contacts,

means biasing said contacts closed. latch means for preventing quickreclosure of said contacts by s'aid biasing means, said latch meanseii'ective to latch said contacts in a plurality of open positions atdierent distances apart, respectively, at least the open position ofsaid contacts at which they are latchcd the greatest distance apartproviding 'a safe gap between said contacts, and time delay meansoperative in response to a circuit interrupting operation to actuatesaid latch means at predetermined times thereafter in a manner tosuccessively release said contacts to permit the same to move under theinfluence of said biasing means to said different positions and finallyinto engagement.

6. In a circuit interrupter, a closed arc chamber, separable contacts insaid chamber at least one of which is slidably mounted through a wall ofsaid chamber in a piston-like manner, electroresponsive means having alost motion connection with said one contact to move said one contactvoutwardly of said chamber and away from the other of said contacts andto permit over-travel of said one contact under the influence ofpressure generated in said chamber by the arc struck when said contactsseparate, said arc chamber adapted to be immersed in a body ofinsulating fluid, lower inlet and upper outlet openings for saidchamber, check valves controlling said openings, respectively, andresponsive to pressure in said chamber for closing said openings, atleast said outlet valve being biased to open said outlet contacts. latchmeans for said one contact for automatically latching said one contactupon opening movement. thereof to prevent reclosini movement, said latchmeans effective to latch said one contact in a plurality of openpositions at diil'erent distances from said other contact, re'

spectively, at least the position of said one contact at which it ismaintained the greatest distance from the other of said contactsproviding a safe gap between said contacts, and iluid time delay meansalso immersed in said duid and utilizing the same so as to be operativein response to a circuit interrupting operation to actuate said s latchmeans at predetermined times thereafter in a manner to successivelyrelease said one con-- tact to permit' the same to move to saiddifferent positions and iinaliy into engagement with said other contact,successively, and insure flushing of said chamber after each circuitinterrupting operation prior to reclosure of contacts.

7. In a circuit interrupter, a closed arc chamber, separable contacts insaid chamber, electroresponsive means having lost motion relative tosaid contacts and adapted to separate said con,- tacts at least anamount suicient to strike an arc. means responsive to pressure generatedin said chamber'by an arc to further separate. said contacts, said lostmotion permitting overtravel of said contacts under the inuence ofpressure generated in said chamber by the arc struck when said contactsseparate, said chamber adapted to be immersed in a body of insulatingfluid, lower inlet and upper outlet openings for said chamber, checkvalves controlling said openings, re.

spectively, and responsive to pressure in said chamber for closing saidopenings,'and at least the outlet valve being biased to open said outletpassage to insure opening thereof upon extinguishment of the arc in saidchamber and consequent lowering of pressure, to provide for flushingsaidchamber by flow of said liquid through said chamber after eachcircuit interrupting operation and insure flushing of said chamber aftereach circuit interrupting operation prior to reclosure of said contacts.

8. In a circuit interrupter, a closed arc chamber, separable contacts insaid chamber, electroresponsive means having lost motion relative tosaid contacts and adapted to separate said contacts at least an amountsuiiicient to strike an arc, means responsive to pressure generated insaid chamber by an arc to further separate said contacts, said lostmotion permitting overtravel of saidl contacts under the influence ofpressure generated in said chamber by the arc struck when said contactsseparate, said chamber adapted to be immersed in a body of insulatingfluid, lower inlet and upper` outlet openings for said chamber, checkvalves controlling said openings respectively, and responsive topressure in said chamber for closing said openings and at least theoutlet valve being biased to open said outlet passage to insure openingthereof upon extinguishment ,of the arc in said chamber and consequentlowering of pressure to provide for flushing said chamber by ilow ofsaid liquid through said chamber after each circuit interruptingoperation to insure ushing of said chamber after each circuitinterrupting operation prior to reclosure of sai-d contacts, and saidinlet valve being freely mounted for limited movement so as to b eresponsive to pressures developed in said chamber to close said inlet,and responsive to the pressure due to the head of liquid outside saidchamber to open said inlet.

9. In a circuit interrupter, a closed arc cham'- ber, separable contactsin said chamber at least one. of which isv slidably mounted through awall of said chamber in a piston-like manner, electroresponsive meanshaving a lost motion connection with said vone contact to move said onecontact outwardly of said chamber and away from the other of saidcontacts and to permit overtravel of said one contact under theiniluence of pressure generated in said chamber by the arc struck whensaid contacts separate, said arc chamber adapted to be immersed in abody of insulating fluid. lower inlet and upper outlet openings for saidchamber, check valves controlling said openings, respectively, andresponsive to pressure in said chamber for closing said openings, atleast said outlet valve being biased to open said outlet passage toinsure opening thereof upon extinguishment of the arc in said chamberand consequent lowering of pressure to provide for flushing said chamberby flow of said liquid through said chamber after each circuitinterrupting operation, means biasing said one contact for movement in adirection to engage the other of said contacts, and fluid time delaymeans also immersed in said iluid and utilizing the same so as to beoperative in response to a circuit interrupting operation to delayclosing movement of said one contact a time sufficient to permit thecarrying out of said ilushing opera- 10. In a circuit interrupter, 'aclosed arc chamber, separable contacts in said chamber,electroresponsive means for separating said contacts at leastsufllciently to draw an arc, means responsive to pressure generated insaid chamber by the arc to further separate said contacts, said arcchamber adapted to be immersed in a body of insulating iluid, lowerinlet and upper outlet openings for said chamber, check valvescontrolling said openings, respectively, and responsive to pressure insaid chamber for closing said openings. at least said outlet valve beingbiased to open said outlet passage to insure opening thereof uponextinguishment of the arc in said chamber and consequent iowering ofpressure to provide for flushing said chamber by flow of said liquidthrough said chamber after each circuit interrupting operation, meansbiasing said contacts for movement in a direction to engage the other ofsaid contacts,

and fluid time delay means also immersed in said iluid and utilizing thesame so as to be operative in response to a circuit interruptingoperation to delay closing movement of said contacts a time sumcient topermit the carrying out of said ilushing operation.

1l. In a circuit breaker, separable contacts. electroresponsive meansfor separating said contacts, means biasing said contacts closed, latchmeans for preventing quick reclosure of said contacts by said biasingmeans, said latch means effective to latch said contacts in a pluralityof open positions at different distances apart, respectively, said latchmeans being ineil'ective to latch said contacts at least for apredetermined short distance apart, atleast-the openposition of saidcontacts at which they are latched the greatest distance apart providinga safe gap between said contacts, and time delay means op-` erative inresponse to a circuit interrupting operation to actuate said'latch meansat predetermined times thereafterin a manner to succes- .s sivelyrelease said contacts to permit the same to move under the influence ofsaid biasing means to said different positions and'nally rapidly into.

engagement with said other contact. successively.

12. In a circuit interrupter, a closed arc chamber, separable contactsin said chamber, electrobeing biased closed, latch means for preventing5 quick reclosure' of said contacts by said biasing means. said latchmeans effective to latch said electroresponsive means at a plurality ofpositions wherein said contacts are diiierent distances apart.respectively, at least the open position ot said contacts at whichtheyare iatched the greatest distanceA apart providing a safe gapbetween said contacts, yand time delay means operative in response to acircuit interrupting operation to actuate said latch means atpredetermined times l5 1s iiuenoe of said biasing means to saiddiirersnt positions and ilnally into engagement with other contact,successively.

JAMES M. WAILACE. HERBERT IL RAWLINB. JAMES M. CUMMING, WAYNE S. ABPEY.

ammonta crrsn The following references are of record in the ille of thispatent:

UNITED STATES PATENTS

